This invention relates generally to attachments for gasoline-powered lawn trimmers of the type that use a flexible cord as the active cutting element; more particularly, this invention relates to a device for attachment to that end of a gasoline trimmer which is adjacent the cutting head, for the purpose of maintaining the cutting head at a controlled distance away from a structure or an obstacle around which vegetation needs to be cut.
A powered device that has become very popular in recent years as a yard-care tool is a line trimmer, also sometimes called a string trimmer or cord trimmer. In such devices one or more flexible cords or strings, typically made of nylon or an extruded plastic, are extended for a few inches in a cantilevered manner from a head, and the head is caused to rotate by use of a power unit. When electricity is used to power such a device, an electric motor is mounted in the head, and a power cord extends from a handle through a hollow tube to the motor. When a small gasoline engine is used to power the unit, the engine is mounted near the handle and a rotatable drive cable extends through a hollow tube between the engine and the cutting head. Such vegetation trimmers have been manufactured and sold by many companies, but perhaps one of the best known of them has been The Weed Eater Company of Houston, Tex.
A practical problem in cutting grass and weeds with such devices has been that it is often difficult to manually support the cutting head adjacent some structure or obstacle at just the right position--to allow the rotating cord to come close enough to cut the vegetation but not close enough to impinge too vigorously on the structure or obstacle. For example, if the obstacle is a wire fence around a yard, there is no way that a rotating nylon cord is going to damage the steel fence if the head is accidentally brought too close to the fence. But the wire elements of the fence will act on the relatively soft nylon like narrow, elongated cutters when the rotating cord strikes them; and very soon it will be mandatory that an operator cause some fresh cord to be removed from a storage reel in order to be able to continue cutting vegetation. Even the heavy wires typically used in chain-link fence tend to act like cutting blades when the static wires are contacted by a cord that may be rotating at several hundred revolutions per minute. In fact, chain-link fencing is so notoriously harsh on the standard cord of a line trimmer that it is commonly said that such a fence "eats" nylon cord.
Another example of a vertically oriented structure adjacent which vegetation routinely grows is the wall of a building--such as a house or garage or barn. Of course, a segment of a solid wall will not usually act like a chopper on a nylon cord; but a rotating cord could damage the aesthetic appearance of a solid wall if the cutting head were brought too close or left too long in one position adjacent the wall. The relatively soft aluminum skirting that is frequently placed around the bottom of a mobile home is an example of a vertical member that is deserving of protection against repeated impact from a rotating line. It follows, therefore, that there has been a need for a spatial guide that will allow the cutting head of a gasoline-powered trimmer (also called a gas trimmer) to get close enough to do an effective cutting job on vegetation but not so close as to possibly damage a permanent structure or the trimmer itself.
In an effort to satisfy the above-described need, various devices have been proposed for attachment to line trimmers in order to render them more efficient. (Because the configurations of the cutting heads are significantly different on electrically powered trimmers and gas-powered trimmers, this disclosure will ignore electrically powered trimmers and concentrate on gas-powered trimmers.) Of the proposed attachments, most have addressed the problem of holding the cutting head so that it rotates about a horizontal axis that is a controlled distance above a medium that is to be cut, e.g., the grass along the edges of a sidewalk. An example of such a device is shown in U.S. Pat. No. 4,442,659 to Enbusk entitled "Dolly For Lawn Trimmer and Combination Thereof." Another device is shown in U.S. Pat. No. 4,803,831 to Carmine entitled "Attachment To A Lawn Trimmer." Still another device is shown in U.S. Pat. No. 4,981,012 to Claborn entitled "Apparatus for Converting a Gas-Powered Flexible Line Trimmer for Use as a Lawn Edger." A characteristic shared by all of these devices is that they probably work nicely for their intended uses, but they would not be ideal for use against a chain-link fence or a vertical wall. There has remained a need, therefore, for an economical, lightweight, simple device that can be readily attached to a flexible line trimmer in order to hold the cutting head a fixed distance away from any structure--whether that structure is horizontal (like a sidewalk) or vertical (like a fence). It is an object of this invention to provide such a device.